1. Field of the Invention
The present invention relates to an apparatus and method for automatically controlling interference in a broadband wireless communication system. More particularly, the present invention relates to an apparatus and method for automatically controlling interference in a broadband wireless communication system considering various communication environments, by communicating interference measurement information between adjacent cells.
2. Description of the Related Art
Because an outdoor mobile communication environment and an indoor short-range communication environment have different conditions, different communication systems support communications for the respective communication environments. For example, outdoor mobile communication systems such as Global System for Mobile telecommunication (GSM), Industry Standard-95 (IS-95), Wideband Code Division Multiple Access (WCDMA) and Code Division Multiple Access-2000 (CDMA-2000) have been developed for the outdoor mobile communication environment, and indoor short-range communication systems such as Institute of Electrical and Electronics Engineers (IEEE) 802.11a, IEEE 802.11b and Wireless Fidelity (WiFi) have been developed for the indoor short-range communication environment. The outdoor mobile communication systems and the indoor short-range communication systems have been developed and used in accordance with their respective purposes and communication environments. That is, the outdoor mobile communication systems have been used mainly for voice communication in a mobile environment, and the indoor short-range communication systems have been used mainly for notebook computer-based data communication in an indoor environment.
However, since users' requirements are becoming increasingly diversified and complicated, the next-generation communication systems must be able to integratedly and simultaneously provide a variety of voice/data communication services anywhere in both the indoors and outdoors. In the current environment where an outdoor mobile communication system and an indoor short-range communication system are separate from each other, a scheme of integrating the two separate systems into one system can be easily conceived to satisfy the aforesaid requirements. This scheme, however, has the following problems.
Firstly, the interworking between the two systems is complex and a processing delay may occur. A vertical handover technology such as a Media Independent Handover (MIH) technology is being developed to address this problem, but it still requires a complex protocol and process. Secondly, because the two systems use different frequency bands, it is difficult to use a flexible frequency band. For example, the indoor short-range communication system uses an unlicensed band and the outdoor mobile communication system uses a licensed band. Therefore, it is difficult for the indoor short-range communication system to use a licensed band in order to increase the indoor communication reliability. Thirdly, because a Mobile Station (MS) must have a function for using both of the two systems, the implementation complexity of the MS increases.
One of the methods for addressing the above problems is to miniaturize a mobile Base Station (BS) of the outdoor mobile communication system and install the miniaturized mobile BS indoors. Hereinafter, the miniaturized mobile BS will be referred to as a micro BS. This technique does not experience the problems caused by the interworking between the heterogeneous systems, and enables the service provider to flexibly use the frequency resources. However, according to the above technique, a communication system adapted to the outdoor mobile communication environment is used indoors without modification, and it has a lower efficiency than a system adapted to the indoor short-range communication environment. In addition, the outdoor mobile communication system operates based on a Global Positioning System (GPS), but the indoor short-range communication system has difficulty in using GPS.
A self-configuration function for automatically selecting a variety of optimal parameters in a given communication environment is desired in order to reduce the initialization cost and to implement the efficient operation of the indoor short-range communication system. However, even with the self-configuration function, there are still many unaddressed problems. In particular, the problem of controlling the interference between adjacent cells may greatly affect the system performance. What is therefore desired is the development of an interference control technique using the self-configuration function.